Lock guard



March 17, 1953 F. A. TRAcHsLER LOCK \GUARD Filed April 24, 1950 .LN VEN TOR. FRED A. TRAOHSLEI? ATTORNEYS Patented Mar. 17, 1953 UNITED srares smear OFFICE LOCK GUARD Fred A. Trachsler, Vallejo, Calif;

Application April 24, 1950, Serial No- 157,715}

4 Claims. 1

Thisinvention relates to a lock guard, and more particularly to a device useful with a lock of conventional design to prevent unauthorized opening thereof.

It is av rather common practice for criminals to. open locked doors by means of a sheet of thin material" such as isinglass, Celluloid or the like by slipping the sheet between the jamb and door and against a cam-type lock bolt in order to force the bolt open and thus release the lock to obtain entry. The present invention provides a means to prevent the use of such an implement to effect opening of locked doors and the same is an object of this invention.

Another object of the present invention is to provide a simple and effective means to prevent unlawful opening of a locked closure by means of an attachment which may be readily afiixed to conventional hardware.

Another object is to provide apparatus for the prevention of opening of locked closures by means of an improved strike plate normally affixed to the door jamb. Further objects of the present invention are to provide improved hardware for locking mechanisms for the purposes above set forth and which is inexpensive and simple to manufacture and install; to provide a lock guard which may be aflixed to conventional lock hardware for closures which will not interfere with the normal operation of the closure and which effectively prevents unlawful and undesired opening of locked closures.

Further objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the sev eral views.

In the drawings:

Fig. 1 is a perspective view of a fragment of a door having a cam-type lock bolt and a fragmentary portion of a door jamb equipped with the present invention.

Fig. 2 is a horizontal sectional view of a door and jamb equipped with the present invention and showing a sheet of thin material such as Celluloid trapped in the guard.

Fig. 3 is a front elevation of the lock guard.

Fig. 4 is an end elevation thereof.

Fig. 5 is a perspective View of a fragmentary part of a closure jamb equipped with a modification of the present invention.

Fig. 6 is a horizontal sectional view of a door and jamb equipped with the modification of Fig. 5.

As illustrated and described herein, the present invention is arranged to be attached to a conventional door jamb and is useable with conventional lock hardware particularly wherein the bolt of the lock is provided with acam face. It will be understood, however, that the guard might with equal facility be attached to the door rather than the jamb.

The device is illustrated in Figs. 1-4 and comprises a member designated generally as A attached to strike plate B carried on the door jamb C. The member A surrounds the bolt receiving apertures 2 and 3 for the two bolt lock illustrated. The bolt is illustrated generally at D as provided with a cam face 4. The jamb C, as illustrated, is provided with a conventional door stop E. The door which carries the lock bolt mechanism is designated at F.

Member A is illustrated here as U-shaped and is formed preferably of thin metal or suitable other substance and comprises the two U-shaped plates 5 and B spaced from one another to form a groove or recess 1 which is open from top to bottomof the member and deposed adjacent the door stop E and between the stop and bolt receiving apertures 2 and 3. As illustrated the groove or recess '1 extends continuously around the U- shaped member on the outer side thereof around the top and bottom and the door stop side of the bolt receiving apertures 2 and 3. The plates 5 and B are spaced apart and connected by a web or flange 8 on the inside of the member A and acts as a backing to the groove or recess 1. Obviously, the unit A may be formed by means of casting or other conventional operation to form an integral member or may be assembled from a plurality of elements.

The member A having the marginal groove or recess 1 is provided with a plurality of screw receiving apertures and screws 9 for attachment of the member to the strike plate.

Fig. 2 illustrates a jimmy sheet G formed of Celluloid or the like inserted between the door stop and jamb and indicates how it is trapped in the recess 7 of member A thus preventing the sheet from bearing against the cam face 4 of bolt D to force the bolt open and thus open the door. It will be noted that the width of plate 5, which lies against the jarnb C or strike plate 18, is less than the width of plate 6, which faces the door. Thus the sheet G is trapped between plate 5 and either plate 5 in the recess 1 or between plate 6 and the jamb.

A modification of the invention is illustrated in Figs. 5 and 6. Strike plate i2 is bifurcated at its margin and provided with flanges I3 and M with a recess l6 therebetween directed toward stop E. Flange I3 is larger than flange 14 which lies against jamb C. Recess I6 serves to trap the leading edge of sheet G (Fig. 6) in the same fashion as described with reference to the lock guard described with reference to Figs. 1-4.

The invention has been illustrated and described in specific detail of use and installation for purposes of clarity of understanding and it is intended that various changes in use, design, and installation may be practiced within the spirit of the invention and scope of the appended claims.

I claim:

1. A look guard for use to prevent opening of a cam-type bolt by insertion of a pliable strip between the door and jamb from the stop side of the door comprising a channel-shaped rigid element formed of two substantially parallel plates having a recess therebetween arranged to be interposed between said jamb and said door, one of said plates being adapted to lie close against said door in the vicinity of said bolt between said bolt and said stop, said element being shaped and arranged to be positioned to provide a strip intercepting recess extending partially around said bolt above, below and on the stop side of said bolt.

FRED A. TRACHSLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,814,961 Phillips July 14, 1931 1,822,424 Scott Sept. 8, 1931 1,844,459 Brandon Feb. 9, 1932 1,853,456 Ross Apr. 12, 1932 2,127,891 Starling Aug. 23, 1938 FOREIGN PATENTS Number Country Date 205,943 Great Britain Nov. 1, 1923 

